1. Field of the Invention
The present invention relates to a multi-function integrated polarizer/optical film structure and manufacturing method thereof, and more particularly, to a structure that can utilize optical design coats, polarizer/optical film with different materials on a plurality of substrates to generate an image with high polarization, high transmittance, wide-angle and high contrast characteristics simultaneously and a manufacturing method thereof.
2. Description of Related Art
Liquid crystal displays (hereinafter referred to as LCDs) use two-piece polarizing films to produce a linearly polarized light to achieve the effect of contrast. A backlight module of the LCD provides primary light. The primary light results from liquid crystal twisted to generate the linearly polarized light when the primary light passes through a first polarization film. When the linearly polarized light has passed through a second polarization film, it will generate the effect of contrast.
In fact, under 5% of the original light reaches the viewer when the original light is passed through the refraction, the reflection and the absorption of the multi-layer materials. The absorption rate and the transmittance of a dichroic polarizer affects the brightness of the LCD. The polarizing film controls liquid crystal display contrast and viewing angle. The degree of polarization of contrast and light loss of viewing angle are adjudged to be the measurement parameters of the polarizing film. Therefore, the polarizing efficiency, the transmittance, the contrast and light loss will decide the display effectiveness of the LCD.
Commercial polarizers typically use O iodine as the predominant type; its principle merit is high polarizing efficiency (99.9%) and transmittance (44%-46%). The main disadvantages of the O iodine polarizers are the following aspects: (1) O iodine polarizers have acute light loss in wide viewing, so much O iodine is needed with a wide-angle film to achieve a high contrast performance; (2) O iodine polarizers have poor temperature and humidity; (3) iodine polarizers' mechanical properties are not strong, so O iodine polarizers must have a protective film pasted onto them to strengthen the outside surface; (4) O iodine polarizers can only be pasted onto the outside of the monitor.
Another type of polarizing film is the E liquid crystal polarizing film, which is a novel polarizer at the present. The E polarizing film mainly has a discotic liquid crystal with absorption when the light passes through the discotic liquid crystal, O polarization light is absorbed, but E polarization light can pass through, thereby achieving a linearly polarized light effect. The E polarizing film polarizing efficiency of the best optics at present is approximately 95% and the transmittance is 40%-44%. The advantages of E polarizing film are: (1) its thickness is approximately only 0.3-0.8 micrometers; (2) it is produced in a liquid crystal cell and sited on the LCD.
In contrast to the iodine series and the E type polarizing film, another coat type of polarizing film is a dye series polarizing film, which is mainly an absorption carrier. The influence absorbency parameters of dye series polarizing film are: (1) its absorption coefficient of dye molecules; (2) its increased dye density and (3) its polarizing film thickness. The main advantages of the dye series polarizing film are: (1) it has good temperature and humidity characteristics; (2) it has a diverse number of coat applying choices and (3) it is produced in a liquid crystal cell.
A prior art iodine series polarizer technology can be found in U.S. Pat. No. 4,591,512, a method for making visible range dichroic polarizer material comprising a uniaxially stretched film of polyvinyl alcohol stained with iodine and treated with a borating solution containing a zinc salt. The mechanical properties, and the temperature and humidity characteristics of the polarizer are not good. Besides the body of iodine polarizing film, a protective film with triacetyl cellulose (TAC) is pasted on the upper and lower side. The present iodine series polarizing film thickness is approximately 200 micrometers
The E type polarizer technology of the prior art can be found in, for example, U.S. Pat. Nos. 6,583,284, 6,563,640, 6,174,394, 6,049,428 and 5,739,296. The above technology utilizes coating manufacture to make a polarizing film of the discotic liquid crystal with absorption effect on a surface of a substrate. When a dry process is performed, the polarizing film will become the E type polarizing film. The light produced is E type polarized light when it is passed through the E type, polarizing film.
Another type of polarizing film is the O type polarizing film. The O type polarizing film utilizes a dye coat on the surface of a substrate to forming the polarizing film. The O type polarizer technology of the prior art can be found in, for example, U.S. Pat. Nos. 5,812,264, 6,007,745 and 5,601,884.
A conventional graph of polarizing efficiency and transmittance curves of the O type polarizing film is shown in FIG. 1A. The vertical axis coordinates are polarizing efficiency and transmittance percentage of O type polarizing film. The cross axis coordinate is wavelength. The Figure shows a distribution curve for polarizing efficiency 10 and transmittance 12 for different wavelengths of the O type polarizing film.
A conventional graph of polarizing efficiency and transmittance curves of the E type polarizing film is shown in FIG. 1B. The vertical axis coordinates are polarizing efficiency and transmittance percentage of E type polarizing film. The cross axis coordinate is wavelength. The Figure shows a distribution curve for polarizing efficiency 14 and transmittance 16 for different wavelengths of the E type polarizing film.